Well it is pretty clear Lee Harvey Oswald did not shott Kennedy and by the way thats why Convertibles suck

Another example of that is the death of James Dean. He was driving a Porsche 550 Spyder without having put the seat belts on when he crashed. If he'd driven a car with a roof, he'd probably not have died.

An interesting thing to note is that Abraham Lincoln was assassinated in Ford's Theatre. John F. Kennedy was assassinated in a Ford car named after Lincoln. There are many other coincidences between the two.

I still wonder what they were thinking letting the leader of the free world ride in an open top car, at the height of the Cold War no less.

This was usual everywhere on the world until the terrorism increased in the early 70ies.

Even in one of the hottest spots of tzhe Cold War, in West Berlin. Just an example: /vehicle_186419-Mercedes-Benz-unknown.html
There were many more in the history. JFK was also driven in an open car at his legendary visit there.

And for the visit of your Queen in 1965 in Germany Mercedes Benz has built an open 600.